Electronic technology is used virtually everywhere. Coffee pots, wrist-watches, automobiles, cash registers, personal computers, telephones, and thousands of other types of common electronic equipment are used by people at any time of the day. While electronic devices provide outstanding convenience and benefit to today's society, they also have the potential to interfere with radio communications and other electronic devices.
Electronic devices by their very nature generate radiated and conducted noise. Electromagnetic Interference (EMI) is often a result of non-ideal passive component behavior combined with timing signals. For example, a resistor acts at high frequencies like a circuit comprising a series combination of an inductance and a resistor in parallel to a capacitor, while an inductor acts at high frequencies like an inductor in parallel with a capacitor, and the like. Electronic devices may also include many electrical and mechanical components that can act as unintentional coupling mechanisms. These coupling mechanisms provide signal paths for noise generated by other devices which affect sensitive circuitry. This may lead to interruption of operation or degraded performance of an electronic device or system.
Because the negative impacts of EMI such as interruption of computing device operations, communications, and emergency services are a major concern, intentional and unintentional generation of electromagnetic noise, as well as susceptibility of electronic devices to EMI are regulated by governmental entities in many countries.